The Retrovirus Research Center is a multidisciplinary research center for the study of HIV/AIDS and other retroviruses. Its general goal is to promote and facilitate HIV/AIDS and other retrovirus research in Puerto Rico. The center is sponsored by the Universidad Central del Caribe and its flagship health care facility located in the Bayamon Health Region of Puerto Rico. The Retrovirus Center promotes the study of HIV infection as a multidisciplinary research arena in which the clinical features, immunological, and virological elements, and the psychological and behavioral parameters need to be integrated into a coherent research strategy. The center agglutinates a coalition of multidisciplinary researchers whose interest is to describe and understand key elements that play a role in the progression and/or expression of HIV infection according to an ecological view of the problem. In this proposal we have organized the structure of the Center in three interlacing core facilities, which will provide support for the development of several pilot studies of great interest to our investigators. The role of the Leadership Core is to coordinate and facilitate an intellectually stimulating environment for HIV/AIDS research by playing a proactive role in generating hypothesis-driven studies. It is the implicit aim of the leadership core to promote HIV-related research in the three axis relevant to human disease including the biological, the behavioral, and the psychosocial !imensions. It will establish the guidelines for the study of the multidimensional aspects of HIV disease in the Puerto Rican population. This multidisciplinary vision of our center is responsive to the vision of the National Institutes of Health their role of studying the complexity of diseases. Our patient population is rather unique in that they are mostly Hispanic in origin and between 70-80% have HIV infection directly or indirectly related to substance abuse practices. The Retrovirus Center has an important role in continuing the research agenda with this patient population with the ultimate goal of diminishing the spreading nature of the HIV epidemic in the island. The Leadership Core will provide an administrative infrastructure and logistic to support research activities through its main two core facilities: The HIV/AIDS Data Core and the Laboratory Core.